A dataset of highly accurate homolytic N-Br bond dissociation energies obtained by Means of W2 theory

Homolytic N-Br bond dissociation constitutes the initial step of numerous reactions involving N-brominated species. However, little is known about the strength of N-Br bonds toward homolytic cleavage. We herein report accurate bond dissociation energies (BDEs) for a set of 18 molecules using the high-level W2 thermochemical protocol. The BDEs (at 298 K) of the species in this set range from 162.2 kJ mol^-1(N-bromopyrrole) to 260.6 kJ mol^-1((CHO)₂NBr). In order to compute BDEs of larger systems, for which W2 theory is not applicable, we have benchmarked a wide range of more economical theoretical procedures. Of these, G3-B3 offers the best performance (root-mean-square deviations = 2.9 kJ mol^-1), and using this method, we have computed N-Br BDEs for four widely used N-brominated compounds. These include (BDEs are given in parentheses):N-bromosuccinimide (281.6),N-bromoglutarimide(263.2),N-bromophthalimide (274.7), and 1,3-dibromo-5,5-dimethylhydantoin (218.2 and 264.8 kJ mol^-1).